Just two days ago we heard news from the Wall Street Journal that Apple will be releasing both an iPhone 4 and the upcoming iPhone 5 on Sprint. Up until February of this year, AT&T was the only carrier that had the privilege of selling the iPhone. Then, Verizon came into the mix with its CDMA version. That left T-Mobile and Sprint customers looking longingly at the iPhones of their AT&T and Verizon friends.

With the news that Sprint will also be getting the iPhone in the upcoming weeks, the only carrier left out of the party is T-Mobile. However, MacTrast is reporting that T-Mobile may also be getting the iPhone which is rumored to be available in mid-October. Of course, AT&T still intends to acquire T-Mobile, so having T-Mobile sell a phone that is one of the most popular for AT&T only makes sense. According to a “contact within T-Mobile” who has been briefed with the matter, the iPhone 5 will be coming to T-Mobile and will operate at 3G speeds.

Also, current unlocked iPhone 4 phones can only operate at 2G “EDGE” speeds and won’t have certain network-dependent features like Visual Voicemail. Of course, T-Mobile hasn’t confirmed anything, but it said earlier this year that it already has 1 million unlocked iPhones running on its network. Apple and AT&T have also been rumored to be testing iPhone prototypes that are compatible with T-Mobile’s 3G network.

The informant also said the T-Mobile phone would launch in mid-October, which goes along with the other mid-October rumors we’ve been hearing. So, is Apple actually releasing an unlocked iPhone 5 that will be able to run on all four carriers? It would definitely cut shipping and distribution costs if there is only one version of the iPhone 5.